Re: Can I use __gc metamethod directly from Lua?

[joseph stewart <joseph.stewart@...>]

> I'm just curious. Why do you need a __GC method for a table anyway?  
> I tend to always use this for C++ classes where I need to call
> the destructor.

As I mentioned, I'm trying to move some of the gruntwork from the 'C'  
side to the Lua side. Without going into too many details, I have low- 
level "allocation" functions callable by Lua that have items that  
need corresponding "de-allocate" functions to avoid memory leaks. My  
Lua-side code handled creating tables that I'd hoped could "self- 
clean" during the collection cycle.

I'm familiar with doing this on the 'C' side, I was just trying to  
minimize the 'C' code.

-joe

> > -----Original Message-----
> > From: lua-bounces@bazar2.conectiva.com.br [mailto:lua- 
> > bounces@bazar2.conectiva.com.br] On Behalf Of
> > joseph stewart
> > Sent: Saturday, November 25, 2006 3:15 PM
> > To: Lua list
> > Subject: Re: Can I use __gc metamethod directly from Lua?
> >
> >
> > On Nov 25, 2006, at 6:09 PM, Ram Firestone wrote:
> >
> > > __gc only works for userdata values.
> >
> > Ah, I was working off the info at:
> >
> > http://lua-users.org/wiki/MetatableEvents
> >
> > That stinks. There's a lot of busy-work in C that I'd rather do in
> > Lua. Too bad.
> >
> > Thanks for the correction.
> >
> > -joe
> >
> > > > -----Original Message-----
> > > > From: lua-bounces@bazar2.conectiva.com.br [mailto:lua-
> > > > bounces@bazar2.conectiva.com.br] On Behalf Of
> > > > joseph stewart
> > > > Sent: Saturday, November 25, 2006 3:05 PM
> > > > To: Lua list
> > > > Subject: Can I use __gc metamethod directly from Lua?
> > > >
> > > > Hello all,
> > > >
> > > > I'm developing a library binding and to minimize the amount of 'C'
> > > > code I need to write, I want to have Lua handle the __gc  
> > > > metamethod.
> > > > At first glance, this doesn't appear to do what I want. Here's the
> > > > essence of what I'm doing:
> > > >
> > > > mt = {}
> > > > mt.__gc = function() print("gc me") end
> > > > t = {1,2,3}
> > > > setmetatable(t, mt)
> > > > t = nil
> > > > collectgarbage("collect")
> > > >
> > > > I would expect to see "gc me" printed after the collectgarbage
> > > > function call, but I don't.
> > > >
> > > > Am I completely on the wrong track? I've used __gc from 'C' code  
> > > > and
> > > > more or less get what I expect. Is __gc usable from Lua code?
> > > >
> > > > Thanks in advance for any help! When the library is done, I'll  
> > > > share
> > > > it with y'all.
> > > >
> > > > -joe